2e7dc5d37
Denis Vlasenko
2008-11-19
Subject
klogctl: fix a problem where we don't terminate read data with '\0' and then misinterpret it. Code shrink while at it.
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Architecture & Compiler Flags
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Build Log
(log yok)
Commit Diff GitHub →
sysklogd/klogd.c+17 -20
| @@ -42,14 +42,14 @@ int klogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; | |
| int klogd_main(int argc UNUSED_PARAM, char **argv) | |
| { | |
| int i = 0; | |
| - | char *start; |
| + | char *opt_c; |
| int opt; | |
| int used = 0; | |
| - | opt = getopt32(argv, "c:n", &start); |
| + | opt = getopt32(argv, "c:n", &opt_c); |
| if (opt & OPT_LEVEL) { | |
| /* Valid levels are between 1 and 8 */ | |
| - | i = xatou_range(start, 1, 8); |
| + | i = xatou_range(opt_c, 1, 8); |
| } | |
| if (!(opt & OPT_FOREGROUND)) { | |
| bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv); | |
| @@ -57,10 +57,7 @@ int klogd_main(int argc UNUSED_PARAM, char **argv) | |
| openlog("kernel", 0, LOG_KERN); | |
| - | bb_signals(0 |
| - | + (1 << SIGINT) |
| - | + (1 << SIGTERM) |
| - | , klogd_signal); |
| + | bb_signals(BB_FATAL_SIGS, klogd_signal); |
| signal(SIGHUP, SIG_IGN); | |
| /* "Open the log. Currently a NOP" */ | |
| @@ -73,15 +70,14 @@ int klogd_main(int argc UNUSED_PARAM, char **argv) | |
| syslog(LOG_NOTICE, "klogd started: %s", bb_banner); | |
| - | /* Initially null terminate the buffer in case of a very long line */ |
| - | log_buffer[KLOGD_LOGBUF_SIZE - 1] = '\0'; |
| - | |
| while (1) { | |
| int n; | |
| int priority; | |
| + | char *start; |
| /* "2 -- Read from the log." */ | |
| - | n = klogctl(2, log_buffer + used, KLOGD_LOGBUF_SIZE-1 - used); |
| + | start = log_buffer + used; |
| + | n = klogctl(2, start, KLOGD_LOGBUF_SIZE-1 - used); |
| if (n < 0) { | |
| if (errno == EINTR) | |
| continue; | |
| @@ -89,25 +85,25 @@ int klogd_main(int argc UNUSED_PARAM, char **argv) | |
| errno); | |
| break; | |
| } | |
| + | start[n] = '\0'; |
| /* klogctl buffer parsing modelled after code in dmesg.c */ | |
| - | start = &log_buffer[0]; |
| - | |
| /* Process each newline-terminated line in the buffer */ | |
| while (1) { | |
| - | char *newline = strchr(start, '\n'); |
| + | char *newline = strchrnul(start, '\n'); |
| - | if (!newline) { |
| + | if (*newline == '\0') { |
| /* This line is incomplete... */ | |
| if (start != log_buffer) { | |
| /* move it to the front of the buffer */ | |
| - | strcpy(log_buffer, start); |
| + | overlapping_strcpy(log_buffer, start); |
| + | used = newline - start; |
| /* don't log it yet */ | |
| - | used = strlen(log_buffer); |
| break; | |
| } | |
| - | /* ...but buffer is full, so log it anyway */ |
| + | /* ...but if buffer is full, log it anyway */ |
| used = 0; | |
| + | newline = NULL; |
| } else { | |
| *newline++ = '\0'; | |
| } | |
| @@ -121,12 +117,13 @@ int klogd_main(int argc UNUSED_PARAM, char **argv) | |
| priority = (*start - '0'); | |
| start++; | |
| } | |
| - | if (*start == '>') { |
| + | if (*start == '>') |
| start++; | |
| - | } |
| } | |
| + | /* Log (only non-empty lines) */ |
| if (*start) | |
| syslog(priority, "%s", start); | |
| + | |
| if (!newline) | |
| break; | |
| start = newline; | |